Tiki Rudders

Welcome to the Wharram Catamaran Forums

Whether you're looking for an answer to a building problem, want practical advice on the sailing of Wharram designs or simply want to share your experiences, this is the place.

In order to post you must first register or login.

14 posts / 0 new
Last post
Anonymous (not verified)
Tiki Rudders
Has anyone tried more hydrodynamic rudder shapes on the Tikis?? I have the regular, flat 18mm plywood rudders on my Tiki21with the standard tapered aft edge. Has anyone tried a more conventional fatter leading edge?? If so, did it make any difference in rudder performance? Boat performance? Thanks for any feedback :D Cheers Rory
Anonymous (not verified)
Re: Tiki Rudders
Rory, I at least thought about the foil shapes when I recently built my new rudders. :) Being that our rudders are part of the hull shape, canoe stern and all, my first feeling is that it wouldn't make much difference. But I haven't done any tank testing either! Hopefully, this thread will bring those with such experience out of the woodwork :lol:
Anonymous (not verified)
Re: Tiki Rudders
Hi Rory,in the past I,ve owned two tiki 21,s,the first was built by me to plan using the standard rudders.The second tiki 21 I bought locally secondhand but the guy who built her had changed the rudder design slightly.The curved section at the aft of the rudder was extented to give a greater rudder area.Speaking with builder,he believed that the rudder area was to small and tacking the tiki might prove difficult.Needless to say after sailing both tiki,s I found both tacked through the wind without any proplem.I can,t really descibe the shape of the rudder but i do have some pic,s if you were interested(don,t know how to add pics to this reply) I currantly own a tiki 26 called "SCOOBY" but my sailing season is over this year after a boating accident on "SCOOBY" whilst taking down the cruising chute I fell backwards and landed on my back in the cockpit smashing my quad muscle in half.It could be four months before I can work again.Best wishes Phil.
Anonymous (not verified)
Re: Tiki Rudders
I'm the proud owner of the first Tiki 21 that Phil mentions. The rudders are to plan and the leading edge is the same width as the hull tapers down to at that point. Because the rudders are lashed on, there is very little gap between the hull and the rudder and it all just looks right. In terms of performance on the water, she seems to turn pretty quickly too so long as you're moving forward when you attempt the turn and I have not noticed any significant turbulence either. Phil - sorry to hear about your accident. Get well soon.
Anonymous (not verified)
Re: Tiki Rudders
On our Tiki 30 the rudders are not too large. Maneuvering in reverse is a challenge, long straight keels, no prop wash, and small rudder area. With any cross wind you have to accept that you have to turn so as not to fight the bows blowing off. We have sold two Tiki 8 meters ( 26' glass foam) to a beach resort in SW Florida. They will be used for 2 1/2 hr charters off the beach. They moor at night in a marina and have to make a three point turn to exit. One of the terms of my contract is that the boats must turn in reverse. I am going to try some kick up rudders built by Ida Sailor. I believe that the deeper rudder shape will provide more turning force and permit some balancing area to prevent rudder slam in reverse. We will be testing this theory in September. JWD's rudder design is awesome for a private yacht. Totally protected and no stainless to fail. As James says, you spend most of your time trying to go straight, you should have to work to turn not to go straight.I will report our progress. David http://www.boatsmithfl.com
Anonymous (not verified)
Re: Tiki Rudders
Thanks for the replies :P I have no problems with my original rudders except that they vibrate at different speeds. 1st hum start up at about 7-8kts, then disappears. The second hum starts singing when surfing at around 12-14kts!! I actually quite like the vibrations - it feels like Cookie is having fun and humming a tune to herself :lol: I think the vibrations are caused by the fact I have conventional metal pintles that gives a 3/4" gap between skeg and rudders. Do any of you Tiki sailors with lashed on rudders get any vibrations??? Happy sailing, building and dreaming ;) Rory
Anonymous (not verified)
Re: Tiki Rudders
I have a Tiki 30 extended by 2.5 feet. When we built the boat we feared she could not respond good enough with the rudders as per plan. Therefore we built holow and slightly profiled rudderblades and they work very well under all conditions.
Anonymous (not verified)
Re: Tiki Rudders
[quote="boatsmith"]On our Tiki 30 the rudders are not too large. Maneuvering in reverse is a challenge, long straight keels, no prop wash, and small rudder area. With any cross wind you have to accept that you have to turn so as not to fight the bows blowing off. We have sold two Tiki 8 meters ( 26' glass foam) to a beach resort in SW Florida. They will be used for 2 1/2 hr charters off the beach. They moor at night in a marina and have to make a three point turn to exit. One of the terms of my contract is that the boats must turn in reverse. [/quote] I have to motor out of my slip in reverse, a 90 degree turn, continue in reverse down the slip channel, make another turn in reverse into the main channel, prior to going forward. I do it by giving full rudder (near 45 degrees) while turning the prop into the desired direction. Vaea is quite happy to motor in reverse. I have seen, on Scott Brown's board, a line connection between the rudders and the outboard that unifies their motion. The lines go slack when the outboard is raised. I already have enough string back there ;) , so I do it all by hand. I, too, used to have SS pintle/gudgeon hardware, with a large gap between the sterns and rudders. There were large vortexes at these points, so the new lashed rudders should minimize such vortexes, as they are quite close to the sterns now. Before: [img]http://farm2.static.flickr.com/1134/1043319086_fe192a327d.jpg[/img] After: [img]http://farm4.static.flickr.com/3341/3648912507_eeace8ef0d.jpg[/img]
Anonymous (not verified)
Re: Tiki Rudders
Kim, Your rudder reattachment looks great. Hope your Sierra trip was enjoyable. Bet your glad to have your boat back operational. Our motors on the Tiki 8m will be fwd of the aft beam, much less leverage obtained than with the motor aft. Maybe thats a solution. David http://www.boatsmithfl.com
Anonymous (not verified)
Re: Tiki Rudders
Hi Rory, I have the stiched on rudders on Sula 11, just as in the plans. I have no vibration at all at any speed. My old Tri had Pintles Etc, and would start to hum at around 5 knts and sing at over 8knts. :lol: I guess the reason is the gap between, the smaller the gap the less ventilation, or hum. :idea: How is the work up for the Jester coming. keep us informed :?: Best Regards, Jackie.
Anonymous (not verified)
Re: Tiki Rudders
Hi Rory and everyone, Yes I foiled my rudders. I set my table saw at 1 degree and cutprogressively thicker strips off the edge of a 2x4. The maxium thickness was about 3/16 inch. I epoxied the strips to the rudder and then sanded them to a smooth curve. I used the basic rules of wing sections. Dull leading edge and sharp trailing edge, but not real sharp. Maxium draft 30% back from the leading edge. I foiled the port side of the port rudder and the starboard side of the starboard. I believe that a sharp leading edge is the main cause of rudder vibration. Changes in boat handeling are difficult to pin down. I think a tighter turning radius and faster tiller response. There could also be improved upwind performance. espically if you foil both sides of both rudders. The Proof would only come with boat for boat testing. For those who are wondering? Can I sail through a tack without backwinding the jib? NO, but maybe that's just me? I also use pintles and grudgons. I noched the rudders around the hardware so the gap at the transom is a small as possible and the rudders still turn. only one of the three sets of hardware are below the water and that is at the very bottom of the rudder. I have pictures if I can ever figure out how to attach them. sincerely Jim garlow tiki 21 #100
Anonymous (not verified)
Re: Tiki Rudders
David- I'm curious what resort ordered those Tiki 8M's and when you expect to deliver - I'd love a chance to try one out some time, and there don't seem to be any available for charter in the USA right now. (Or am I just not looking hard enough?) --Rich in Colorado
Anonymous (not verified)
Re: Tiki Rudders
Hi All, New here on the Wharram forum. I have recently launched my re-built Tiki and on the first day out making sure nothing went wrong or broke, I was broad reaching at 12.5 knots when I had time to look at the speed and possibly a little more at other times. I have the rudders lashed to the hulls as-per-plans and no vibration was heard throughout that sea-trial. However, on other cats I have found there is normally a hum/vibration, but then there is normally a gap in front or on top(if through hull rudder shaft)of the rudder. Re-tacking, Compared to my old Hinemoa she tacked well and surprisingly easily, even in 2 meter sea's in 25 knots of wind on my first passage through Looe Channel, off Selsey Bill when the cabin hatch went for a swim(retrieved 2nd attempt!) Thanks Andy
Anonymous (not verified)
Re: Tiki Rudders
Hi Rich, We will have one of the oats sailing at the Wharram Rendezvous in Palm Beach in Dec. We will be taking people for demos on the 8m and our Tiki 30. There will also be a number of other Wharrams there as well. There is a post under the news section here with more info. Sorry I didn't respond earlier I was at the Annapolis sailboat show. Many folks loved our boat. It looked like pure fun amidst the condomarans. David http://www.boatsmithfl.com
Log in or register to post comments